has plasma membrane part gamma-delta intraepithelial T cell CD8-alpha alpha positive, gamma-delta intraepithelial T cell https://cellxgene.cziscience.com/cellguide/CL_0000802 CD8-positive, gamma-delta intraepithelial T-lymphocyte The CD8-alpha alpha positive, gamma-delta intraepithelial T cell are a subset of intraepithelial lymphocytes (IELs), a highly heterogeneous population of immune cell that resides within the epithelial layer of mucosal barriers. CD8-alpha alpha positive, gamma-delta intraepithelial T cell are predominantly found in the gastrointestinal tract. They are characterized by the expression of both CD8-alpha-alpha homodimer and the gamma-delta (γδ) variant of the T cell receptor (TCR). CD8-alpha alpha positive, gamma-delta are thought to represent the most typical γδ IEL subset in the intestine. The IELs in the intestines are constantly and directly exposed to antigens in the gut lumen and form the first line of immune defense against invading pathogens. Unlike conventional T cells, IELs in the intestine are antigen-experienced and do not require priming. CD8-alpha alpha positive, gamma-delta intraepithelial T cells fall into a subgroup of ‘natural’ IELs, which acquire their activated phenotype in an ‘alternative’ self-antigen-based maturation process in the thymus. CD8-alpha alpha positive, gamma-delta intraepithelial T cell have several key functions. They help maintain the integrity of the epithelium and repair the epithelial barriers in response to physical and inflammatory injury by secreting various factors, including TGFβ1, TGFβ3 and keratinocyte growth factor (KGF). These cells also provide immediate, front-line defense against pathogens. They retain the ability to respond directly to stress-associated and infected cells independent of antigen-presenting cells and major histocompatibility complex molecules. They do this through recognition of antigens present on the surfaces of stressed or infected cells. Once activated, these cells initiate a rapid immune response by releasing cytotoxic granules and engaging death receptors, processes that eliminate harmful cells. Furthermore, CD8-alpha alpha positive, gamma-delta intraepithelial T cells have been implicated in regulatory functions, including in antibody class switching and immunoglobulin A (IgA) production and IL-10-dependent oral tolerance. Dysregulation CD8-alpha alpha positive, gamma-delta intraepithelial T cells is linked to several inflammatory disorders including celiac disease, inflammatory bowel disease, and others. Therefore, the CD8-alpha alpha positive, gamma-delta intraepithelial T cell plays a significant role in not only direct pathogen defense but also in the maintenance of epithelial tissue integrity and homeostasis. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) CD8-positive, gamma-delta intraepithelial T-cell CD8-positive, gamma-delta intraepithelial T lymphocyte A gamma-delta intraepithelial T cell that has the phenotype CD8-alpha alpha-positive. IEL intraepithelial lymphocyte T-cell surface glycoprotein CD8 alpha chain